1. Field of the Invention
The present invention relates to a mount for translating linear motion to an object, such as an optical component.
2. Description of the Related Art
Precision linear motion translation devices have become important in recent years, particularly in aerospace and semiconductor industries, for translating or conveying rectilinear motion to an object. In particular, parallel motion mechanisms employing parallel flexure linkages are useful for translating a frictionless linear motion to an object of interest. Such parallel motion mechanisms are typically referred to as “porch swing” mechanisms, because the rectilinear movement that is translated to the object during operation of these mechanisms resembles the linear movement of a glider type porch swing.
A simple linear motion device employing parallel flexure linkages is depicted in FIG. 1. In particular, device 1 includes a support or base plate 2, and a carriage 4 separated at a selected distance from and secured to the base plate via a pair of flexure blades 6. Flexure blades 6 are disposed at the longitudinal ends of the carriage in parallel alignment with each other and pivot at their attachment points with the carriage. A driving device 8 (e.g., a micrometer head) is secured to the base plate and engages the carriage at one of its longitudinal ends, via a plate 10, to effect rectilinear movement of the carriage along an axis X when the driving device is moved in that direction. Movement of the driving device forces parallel flexing of the flexure blades to displace the carriage a desired distance along the X axis while minimizing or preventing rotational movements of the carriage about the X axis as well as other axes transverse to the X axis.
Flexure based rectilinear movement mechanisms of the parallel flexure or “porch swing” type have been designed for use in optical instruments such as interferometers. The flexure blade linkages of such mechanisms are particularly suitable for use in optical instruments associated with aerospace applications because they extend the operational life of the mechanism in comparison to mechanical linkages required to perform the same movements.
However, attempts at employing a linear translation porch swing device for optical instruments utilized in space flight applications has met with limited success due to the many difficult challenges and requirements associated with such applications. For example, issues such as mass, size and robustness of the device, power requirements for generating precision movements of the device, and the ability of the device to perform with precision for extended periods of time (e.g., at least ten to fifteen years of a space flight) are important considerations in aerospace applications. Other issues that are important to consider in designing a linear translation device for aerospace applications are the sensitivity and operability of the device to large temperature fluctuations, sensitivity of the device to shock and external vibrations (e.g., during launch conditions in a space shuttle), sensitivity of the device to gravity orientation, and any adjustments required of the device to achieve high precision performance.
Thus, there exists a need to provide a precision frictionless linear translation device that performs well under the conditions encountered in aerospace as noted above, minimizes the energy requirements associated with operation of the device and is suitably dimensioned and of a suitable weight to satisfy space flight requirements.